In one conventional form of power transmission belt, a plurality of longitudinally extending tensile cords are provided in a cushion rubber section thereof. The belt further defines an inner compression section conventionally formed of an elastomeric material, such as rubber.
In one form of such belt, short fibers are provided in the rubber of the cushion section.
It is further conventional to provide cover fabric on the outer surface of the belt and on the inner surface of the compression section of the belt.
By maintaining the side surfaces of the V-belt raw edge, a high friction coefficient with the confronting surfaces of the pulley groove is obtained. The provision of the transverse fibers in the compression section minimizes deformation of the belt in the driving operation as a result of the relatively large lateral pressure on the compressed part of the belt.
In one prior art construction, the compression layer is formed of an inner layer and an outer layer having different hardnesses. A problem has arisen, however, in such construction in that separation of the layers along their interfaces tends to occur after a relatively short use of the belt due to the deterioration of adhesion between the layers caused by heat generated in the driving operation and as a result of their relatively large lateral pressure acting on the compression section.